• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.85-90
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• 1998

The business of manufacturing is increasingly becoming time-compressing, precise and long-life oriented, owing to various needs from the consumers and harsh global competition. With the emergence of the layer laminate manufacturing method, it is possible to produce prototypes directly from 3D CAD and additive process, the production time and cost have shortened dramatically. However there are some problems like surface-step, dimensional deviation and warp. A newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising rapid tooling method because of high density characteristics and low dimensional shrinkage below 0.1％ during sintering and infiltration. By this process, we have realized significant time savings bypassing the wait for prototype tooling and cost savings eliminating the expense of conventional prototype tooling process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.191-194
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• 1995

The business of manufacturing is increasingly becomeing time-compresssing, precise and long-life oiented, owing to various needs form the consumers and harsh global competition. with the emergence of the layer laminate maunfacturing methods, it is possible to prototypes directly from 3D CAD and additive process, the production time and cost have shortened dramatically. However there are some problems like surface-step, dimensional deviation and warp. A newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising repid tooling method because of high density charateristics and low dimensional shrinkage below 0.1% during sintering and infiltration. By this process, we have realized significant time savings bypassing the wait for prototype tooling and cost savings eliminating the expense of conventional prototype tooling process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.159-166
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• 2010

The speed at which products are developed and released to market is tightly linked to profitability and market share. Hence, many companies are still in a desperate need of real Rapid Tooling (RT) technologies which can really help to expedite their prototype tooling and pre -production tooling for injection molding. Many other companies that have been very skeptical of RT technologies developed so far are working on Hybrid Tooling (HT) that can really meet the market standards. With the conviction that HT can be a reliable alternative for current RT technologies, this paper describes the experimentation how HT process has been being successfully established and effectively applied with typical case studies. Through the experimentation, Ceramic-filled SLA tooling was found to be aptly suited for the low grade mold, and Metal SLS tooling was found to be aptly suited for the medium volume mold both in terms of the lead time, dimensional accuracy, and tooling cost.

• Transactions of Materials Processing
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• v.15 no.6 s.87
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• pp.436-440
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• 2006

A rapid tooling (RT) method fur the resin transfer molding (RTM) have been investigated. We fabricated a curved I-beam to verify the method. After creating a three-dimensional CAD model of the beam we fabricated a prototype of the model using a rapid prototyping (RP) machine. A soft mold was made using the prototype by the conventional silicone mold technique. The procedure and method of mold fabrication is described. The mold was cut into several parts to allow easier placement of the fiber preform. We conducted the resin transfer molding process and manufactured a composite beam with the mold. The preform was built by stacking up eight layers of delicately cut carbon fabrics. The fabrics were properly stitched to maintain the shape while placement. The manufactured composites beam was inspected and found well-impregnated. The fiber volume ratio of the fabricated beam was 16.85%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.303-306
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• 2001

To shorten the delivery time for new products, a lot of prototype plastic parts manufacturing technologies have been developed including injection molding, vacuum casting, thermal forming and so on. Among them, RIM is becoming one of a important soft tooling methods to produce prototype and mass production parts within short time. Further more, as the rapid prototyping technology based tooling methods are playing an important role in prototype manufacturing industry, the utility of the RIM is increasing. But few analyses and mold design techniques have been developed so far due to its chemical and mechanical complexity during the packing and curing process. This research suggests mold gate design criteria to prevent bobbles from molded parts through simplified mathematical model and change of bubble sizes according to the geometry of the molded parts through experiments. Also this study shows the differences of bobble generation mechanism between RIM and injection molding.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.203-210
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• 2006

This paper focuses on the development of RT technology suitable for manufacturing a small quantity of metal prototype of a precise part from an RP master. Dimensional accuracy and surface roughness are evaluated from Thermojet part of a 3D printer, and effective post-processing method is introduced. Investment casting is done using a prototype built from 3D printer as a wax pattern. Ceramic shell investment casting technique is developed to build a prototype with materials mostly wanted. Also, experimental result shows this research is very useful in manufacturing of a small quantity of functional part or a test part of a specific material.

• Journal of Powder Materials
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• v.7 no.2
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• pp.102-109
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• 2000

With the emergence of the 3D CAD, it is possible to create a physical part directly from a digital model by accumulating layers of a given material. The technology is being widely used for checking designs, to create master models for rapid tooling, and for reverse engineering. However, in general, a model created by rapid prototyping technology is made of soft material that cannot be used as mass prouduction hard tool. Newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising rapid tooling method because of high density characteristics and low dimensional shrinkage below 0.1% during sintering and infiltration. Through this process, we have realized significant time and cost savings eliminating the expense of conventional prototype tooling process.

• Design & Manufacturing
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• v.2 no.2
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• pp.20-24
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• 2008

Recently, the study for production technology is focused on cycle time reduction as various products are manufactured. In order to manufacture tool and die, rapid prototyping and rapid tooling are researched. Stereolithography apparatus, selective laser sintering, 3D printing, laminated object manufacturing are developed in rapid prototype. The purpose of this study is to develop rapid tooling technology using thermal spray process. This technology is not well-known to korea, but this study will be contributed in development of domestic molds industry through continuous research and development.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.6
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• pp.661-669
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• 2002

Rapid tooling technique enables us to make dies and molds that produce prototype parts with the correct material at a substantially reduced cost and time. In this study, experiments on selective laser sintering of tungsten carbide-cobalt mixture were carried out to find optimal sintering conditions that will be applied to rapid metal tooling. The experiments were carried out within an air, an argon and a nitrogen atmosphere. Coupons of single layer were sintered at various laser powers, scanning speeds and scan spacings. Very severe oxidation took place within an air atmosphere. The oxidation is reduced significantly within an argon and a nitrogen atmosphere. The thickness of the sintered coupons is increased as the energy density, the laser energy Per unit scanned area, is increased. Several multi-layer sintering experiments were also carried out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.181-194
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• 1992

Deformations of a prototype vacuum chamber for the Storage Ring of the Pohang Light Source Project, due to both welding and baking, have been measured using the Optical Tooling Technique. The measurements aim for the acquisition of data for inspection of the chamber design and for the establishment of positional relationship with the components surrounding the chamber. The effectiveness of the Optical Tooling Technique, as a replacement for the conventional mechanical precision measurement, has been proved by the successful measurements of the vacuum chamber deformations.